A customer of mine wants to use two interconnected clatalyst 4500R switch on a redundant industrial network. One computer is connected to a 2800 switch that is connected to both 4500R. On the otherside of the network, a PLC is also connected to a 2800 that also connect to both 4500R.
I know that spanning tree protocol will prevent the loops and close redundant port. In case of failure of a network device, then the redundant port will be opened and the traffic will pass through this new route.
What I want to know is on wich OSI level this works. how does the switch sees that traffic can not be forwarded. We do not use TCP/IP for our connection, but directly mac adresses, will this trafic also be routed to the correct adress in case of failure?
STP works on layer 2 of the OSI reference model. It works on the basis of mac-addresses of the bridges/switches and there are packets called BPDU's( Bridge Protocol Data Unit) which are exchanged between the switches and have information which leads to the STP process completion.
STP process puts redundant paths into blocking mode and in case of failure of the primary path, stp process is again calculated to open up the blocking port.
Please find below the link which would give you further clarity on the STP process.
This is actually a pretty cool feature, i didn't even know it existed until I was looking for a solution to advertise a subnet (prefix in BGP talk), only if a certain condition existed. This is exactly what conditional advertisements does
j ai une question j ai achete un routeur cisco 887VA-k9 , je le configuré avec la configuration ci- dessous
si je le lier avec mon pc portable sur l un de ses ports directement ça marche toute est bien ( la connexion internet + m...
Attached policy provides CLI access to the Cisco 4G router over text messaging. Two files are in the attached .tar file:
2. PDF with instructions on how to load and use the .tcl file.